Mark Field’s launch on Tuesday of a new group “Conservatives for Managed Migration” received a warm welcome from the immigration lobby and from the Labour party but it is hard to take them seriously. The group appears to have very little knowledge of the actual policy issues and certainly have no constructive suggestions; they simply call for the net migration target to be dropped from the next manifesto.

Indeed their whole argument is based on a false choice between immigration control and an open economy. An immigration target does not remotely threaten our open economy, but it does provide a focus for government policy which has proved invaluable. Non-EU migration is down by 35 per cent to its lowest level since 1998, and thousands of bogus applicants have been refused. There is little doubt that the existence of the target and the firm commitment to it by the Home Secretary and Prime Minister has been crucial in starting to get immigration under control. If this progress had not been made we would now be facing net immigration approaching 300,000 a year, with huge implications for our population, public services and social cohesion.

Mr Field wants to see a positive case for welcoming those who can make our country greater. Nobody could disagree with that sentiment, but not all of the nearly four million foreign migrants under Labour fall into that category. He also calls for “a sensible, planned and rational policy”. Easily said – but policies need objectives, and it is very far from a “hysterical reaction” to set a clear objective and work towards it.

It would help if this group were to get their facts right. Regurgitating complaints of industry and academia, he claimed in the Sunday Times last weekend that “Time and again, businesses and globally competitive universities tell me of the barriers they face in securing entry to Britain for the people we should be welcoming” In fact, there is no evidence that there are any serious difficulties for industry. The cap on work permits, which has been set at about 20,000 a year, has only ever been half taken up. There are no restrictions on the cross posting of international staff, providing that they earn £40,000 a year. Furthermore, business is free to employ any foreign graduate of a British university provided that they pay them at least £20,300 a year and, of course, that the work is at graduate level. The complaints that he is repeating reflect more a visceral dislike of any government regulation, whether in the public interest or not. They have very little basis in fact.

As for the complaints from universities, the number of visas issued for university study have actually gone up by 17 per cent over the last three years. The reduction has come in visas for higher education, notably from India, where abuse was rife. There is certainly not, as he claimed, “an explicit objective to reduce student numbers”. There is, however, a strong determination to root out bogus colleges and bogus students.

If “Managed Migration” want an intelligent discussion they could turn their attention to students from outside the EU. As the reform of the immigration system has proceeded, it has become increasingly clear that the central issue for non EU migration is that of students who stay on illegally. According to Home Office research, about 20 per cent acquire a legal right to remain but, according to the International Passenger Survey, only about 30 per cent are actually leaving. So the broad picture is that about half of all non-EU students are unaccounted for – and they could amount to as many as 100,000 a year. Clearly, we cannot go on expanding our higher education “invisible exports” when so many seem to be staying on invisibly, adding to net migration and the associated pressure on population, public services and housing. That is a bullet that must be bitten if net migration is to be curbed.

Some voices are suggesting that the focus should now be on gross immigration, rather than net. However, the effect of that would indeed be to put pressure on those temporary workers and genuine international students who we do wish to encourage. Net migration is undoubtedly the right approach, with a focus on non-EU migration which the government can directly control.

This still leaves a gaping hole – EU migration which, inevitably, has now become part of the debate about our continued membership of the union. If, in the end, our partners refuse to allow us to impose any additional controls on EU workers, there will be a straight choice between controlling our borders and remaining in the Union. That could turn out to be a close vote.

Meanwhile, those who are serious about managing migration need to get a grip of the facts and some idea of the policies in operation. The uncritical repetition of largely unfounded complaints does absolutely nothing for the reputation of the UK about which this group claims to be concerned.

An effective immigration system is essential to a free economy and an open society. Unfortunately, the system ran out of control under Labour and is only slowly being brought back to health. Ill-founded criticism should have no place in a debate of such importance to our future and of such real concern to the public, over 70 per cent of whom consistently say that they want less immigration.